Improvement in oil-well pumps



UNITED STATES PATENT OFFICE.

EDVARD H. ASHCROFT, OF LYNN, MASSACHUSETTS.

IMPROVEMENT IN OIL-WELL PUMPS.

Specitication forming part of Letters Patent No. 4 5,573, dated December 27, 1364.

To all whom it may concern: section of the tubes; Fig. 3, ahorizontal sec. Beit known that I, EDWARD H. AsHoRoFT, tion of the same in line a b.' of Lynn, in the county of Essex and Sta-te ot' A represents the lining-tube; B and C, Massachusetts, have invented a new and lmthe upper and lower valve-boxes G and proved Method of Relieving Oil-Well Pump- C", the escape gastubes; D and D', the stop- Valves; and I do hereby declare that the t'olcocks. It will bc seen the valves or boxes lowing is a t'ull and exact description thereof, are located as usual, and the pipes G and C" reference being had to the accompanying pass outside of the main or lining tube, one diawings, and to the letters of reference entering it between the boxes, the other bemarked thereon. low the lower one. To the upper en d of each ln many instances it has bren found that one of these a stop-cock is attached. Under oil could not be pumped from wells which ordinary circumstances these are kept closed, were known to be iiowing or yielding, and but at any time they can be opened to permit upon investigation it was ascertained that the the to escape from below and between the picssuie of the gases at the bottom of the boxes, relieving the samefrom injurious presswell had forced open the lower valvekeeping ure. When the ow ot' gas ceases, the cocks it open-its own speciiic gravity or weight are closed and pumping resumed. not being sufficient to overcome the same, and What l claim as new, and desire to secure consequently the pump would not Work nor b v Letters Patent, isbring up the oil. rThe tubes C and C, for the escape of gas rlhe object of my invention is to remedy from the bottom of oil-wells, thereby relieving this evil by providinga means of escape for the the lower valve-box from injurious pressure gases below the lower box and between it and or opening, which prevents the operation ot' the upper box, and this I do by providing the pump, the samelocated and operated subsmaller tubes or pipes, which pass outside of stantially as described.

the lining or main tube and which open into it at proper points, having stop-cocks above E' H ASHCIMOFT the surface ot' the ground. \\"itnesses:

In the drawings, Figure 1 represents a side JOHN S. HOLLINGSHEAD, elevation of my invention 5 Fig. 2, a vertical JOHN D. BLUOR. 

